In which situation would a full file buffer be necessary during antivirus scanning?

A full file buffer is necessary during antivirus scanning primarily in proxy-based inspection mode because this mode requires the entire file to be loaded and scanned before it is transmitted to the endpoint. In proxy-based mode, the FortiGate device acts as an intermediary between the client and the server, meaning it must receive the complete file to perform a thorough analysis and adhere to security policies effectively.

When scanning files in proxy-based mode, the FortiGate can analyze all aspects of the file (including its contents and structure) before allowing it to reach its destination. This is essential for effective threat detection and prevention. Users benefit from ensuring that no harmful files reach their network under this inspection method.

In contrast, flow-based inspection mode, on the other hand, checks packets in real-time without capturing the entire file, which is appropriate for speed and can handle larger files more efficiently without needing to buffer the whole content. Thus, the requirements for buffering differ significantly between these modes of inspection.